One method of environmentally protecting and/or electrically insulating an object is by providing an expanded elastomeric tube which is maintained in the expanded condition, positioned over the object to be protected and then allowed to contract into intimate contact with the object. "Expanded condition" as used herein refers to radial stretching of the elastomeric tubing, but not significant longitudinal stretching. Such tubing finds particularly useful application in the electrical industry where it is used to cover, environmentally protect and electrically insulate electrical connections, such as splices between two electrical conductors.
There are several methods of maintaining elastic tubes in the expanded condition prior to application. These methods usually involve the use of a rigid support structure which has dimensions greater than the dimensions of the elastic tube in an unstretched condition. Suitable support structures may be positioned inside or outside the expanded tube to firmly hold the tube in an expanded condition.
U.S. Pat. No. 3,515,798, assigned to the assignee of the present invention, is hereby incorporated by reference and discloses an internal support for an expanded elastomeric tube in the form of a continuous narrow strip of tough flexible material in the form of a substantially rigid closed helix having adjacent coils interconnected. This helical internal support is removed by pulling one end of the strip of material and thereby unwinding and removing the internal support to allow the tube to contract.
U.S. Pat. Nos. 4,585,607; 4,070,746 and 4,656,070 disclose expanded elastomeric tubes which are retained in an expanded condition by an external form to which the expanded tube is bonded. The external form is separated from the expanded tube either by chemically weakening the bond between the form and the tube or breaking the form and peeling it away from the tube.
The problem associated with any of the prior patents described above is disposal of the retaining device or its remnants.